Quantum information and computation, based on quantum correlations of quantum systems, is one of the promising new fields of physics and information science. Entanglement is the key resource of quantum information processing. However, it is shown recently that quantum entanglement is not the only kind of quantum correlations useful for quantum information processing. Quantum systems without any...

Indices of marital discord and mother-child affective processes were used to predict levels of negativity children displayed with unfamiliar peers. Thirty-nine mothers and their 5-year-olds were observed with 5–7 other mother-child dyads during a 30-minute free play session. Mother and child negativity were coded and two types of marital discord were assessed via mother self-report: affiliative...

OBJECTIVE To determine the independent effects of parental depression and family discord on psychopathology in offspring at high and low risk for major depression. METHOD One hundred eighty-two offspring of depressed or nondepressed parents were followed over 10 years. In direct interviews, parents' and offspring's psychopathology was evaluated by raters blind to parents' clinical status. Fiv...

Gaussian quantum discord is a measure of quantum correlations in gaussian systems. Using gaussian discord, we quantify the quantum correlations of a bipartite entangled state and a separable two-mode mixture of coherent states. We experimentally analyze the effect of noise addition and dissipation on gaussian discord and show that the former noise degrades the discord, while the latter noise fo...

Entanglement is known to be an essential resource for many quantum information processes. However, it is now known that some quantum features may be acheived with quantum discord, a generalized measure of quantum correlation. In this paper, we study how quantum discord, or more specifically, the measures of entropic discord and geometric discord are affected by the influence of amplitude dampin...

We extend the quantum discord to continuous variable systems and evaluate Gaussian quantum discord C(ϱ) for bipartite Gaussian states. In particular, for squeezed-thermal states, we explicitly maximize the extractable information over Gaussian measurements: C(ϱ) is minimized by a generalized measurement rather than a projective one. Almost all squeezed-thermal states have nonzero Gaussian disco...

Two prominent and widely studied notions of quantum correlations are discord and entanglement, with the latter occupying a central place in quantum information theory, while the former being regarded of marginal significance and even being criticized by some researchers, although the deep relations between them have been revealed in recent years. Discord and entanglement, being indistinguishabl...

We identify signatures of chaos in the dynamics of discord in a multiqubit system collectively modelled as a quantum kicked top. The evolution of discord between any two qubits is quasiperiodic in regular regions, while in chaotic regions the quasiperiodicity is lost. As the initial wave function is varied from the regular regions to the chaotic sea, a contour plot of the time-averaged discord ...

Quantum discord characterizes "nonclassicality" of correlations in quantum mechanics. It has been proposed as the key resource present in certain quantum communication tasks and quantum computational models without containing much entanglement. We obtain a necessary and sufficient condition for the existence of nonzero quantum discord for any dimensional bipartite states. This condition is easi...

We revisit the upper bound of quantum discord given by the von Neumann entropy of the measured subsystem. Using the Koashi-Winter relation, we obtain a trade off between the amount of classical correlation and quantum discord in the tripartite pure states. The difference between the quantum discord and its upper bound is interpreted as a measure on the classical correlative capacity. Further, w...